Several means have been identified which may cause the failure in operation of a rolling lobe airspring. Aside from the obvious possibility of the defectiveness of the parts themselves, the major causes of the failure of the assemblies can be attributed to the lack of proper assembly. The assembly generally involves the attachment of the flexible tubular air sleeve to an end member by means of some type of clamping ring. Generally, one end member may be an end plug while the other end member is some type of piston, however, either two end plugs or two pistons may be used in an airspring assembly.
Factors which must be balanced to determine the adequacy of the connection are the degree of compression of the sleeve between the end member and the clamping ring, the amount of surface area on the end member which is in contact with the sleeve, the ease with which the clamping ring may be crimped or swaged against the sleeve and the ease with which the given components can be held in a preassembled stage prior to the crimping stage without having a tendency to fall out of alignment with each other.
It is necessary to provide a sufficient amount of compression of the sleeve against the end member in order to provide a good air seal during the operating life of the airspring assembly. However, the amount of compression should not be so great as to cause a cutting of the air sleeve by either the clamping ring or the surface area of the end member as the airspring member is inflated and flexes through its normal operation. A considerable amount of force is exerted upon the connection during normal operation which has a tendency to try to pull the air sleeve out from between the clamping ring and the end member. Another problem occurs when either through normal operation or through other causes the clamp ring becomes dislodged from its position of being centered in the clamping area to such an extent that it can no longer seal the sleeve to the end member.
It is an object of the present invention to provide an airspring end member having a trough area which maximizes the pullout force required to remove the air sleeve between the end member and the clamping ring.
It is a further object of the present invention to provide an airspring end member having a trough area which prevents axial movement of a clamping ring used in combination therewith.
It is a still further object of the present invention to provide an airspring end member having a trough area which minimizes the possibility of cutting into the flexible tubular sleeve used in combination therewith.
It is yet another object of the present invention to provide an airspring end member having a trough area so designed as to aid in the preassembly of the airspring assembly as well as to provide the self-centering of a clamping ring used in combination therewith.